Synthesis of Selenium-Decorated N-Oxide Isoquinolines: Arylseleninic Acids in Selenocyclization Reactions.

Herein, we describe the use of benzeneseleninic acid derivatives (BSA) as a bench-stable and easy to handle selenium reagent to access 4-(selanyl)isoquinoline-N-oxides through the selenocyclization of o-alkynyl benzaldehyde oximes. The reaction is conducted in refluxing methanol, allowing the thermal generation of electrophilic selenium species in situ. By this new protocol, a library of 19 selenium-decorated N-oxide isoquinolines was accessed in up to 96% yield with an outstanding substrate tolerance and the feasibility to scale it up 10 times (from 0.25 to 2.5 mmol).

Bioactivity of selenium-containing pyridinium salts: Prospecting future pharmaceutical constituents to treat liver diseases involving oxidative stress.

Redox imbalance leads to oxidative stress that causes irreversible cellular damage. The incorporation of the antioxidant element selenium (Se) in the structure of pyridinium salts has been used as a strategy in chemical synthesis and can be useful in drug development. We investigated the antioxidant activity of Se-containing pyridinium salts (named Compounds 3A, 3B, and 3C) through in vitro tests. We focused our study on liver protein carbonylation, liver lipoperoxidation, free radical scavenging activity (1,1-diphenyl-2-picryl-hydrazil [DPPH]; 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid [ABTS]), and enzyme-mimetic activity assays (glutathione S-transferase [GST]-like; superoxide dismutase [SOD]-like). In addition, 2-(4-chlorophenyl)-2-oxoethyl)-2-((phenylselanyl)methyl)pyridin-1-ium bromide (3C) was selected to evaluate the acute oral toxicity in mice due to the best antioxidant profile. The three compounds were effective in reducing the levels of protein carbonylation and lipoperoxidation in the liver in a µM concentration range. All compounds demonstrated scavenger activity of DPPH and ABTS radicals, and GST-like action. No significant effects were detected in the SOD-like assay. Experimental data also showed that the acute oral treatment of mice with Compound 3C (50 and 300 mg/kg) did not cause mortality or change markers of liver and kidney functions. In summary, our findings reveal the antioxidant potential of Se-containing pyridinium salts in liver tissue, which could be related to their radical scavenging ability and mimetic action on the GST enzyme. They also demonstrate a low toxicity potential for Compound 3C. Together, the promising results open space for future studies on the therapeutic application of these molecules.

Visible Light and Triselenium Dicyanide (TSD): New Horizons in the Synthesis of Organic Selenocyanates.

Herein, we describe a new method for the synthesis of α-carbonyl selenocyanates by reacting triselenium dicyanide (TSD) and styrenes under blue light irradiation and O2 atmosphere. The reactions are triggered by the formation of Se-centered radical species, followed by the addition/oxidation of the styrene π-bond. α-Carbonyl selenocyanates and α-hydroxy selenocyanates were obtained in moderate to excellent yields from aryl- and alkyl-substituted alkenes, respectively. It was demonstrated that α-carbonyl selenocyanates could be used as a synthetic platform in a multicomponent reaction strategy to prepare 2-phenylimidazo[1,2-a]pyridine derivatives, which were evaluated for their photophysical properties. Overall, this new method provides a useful tool for synthesizing α-carbonyl selenocyanates, and demonstrates their potential for use in the synthesis of other compounds, thus giving new synthetic opportunities to construct organic selenocyanate compounds.

Hydrodynamic radius dictates sensitivity of x-ray detectors based on the radiomicrofluidic synthesis of colloidal silver.

A radiolytic synthesis of silver nanoparticles was carried out in combination with a microfluidic method to produce liquid radiation detectors. The detector response was analyzed by correlating the absorbed dose with the dispersion's absorbance and with the hydrodynamic radius (HR). Samples were irradiated with x-rays of varying beam energies and dose rates and the data were discussed to elucidate how nucleation and growth processes are affected by the radiation quantities. Results reveal that HR does not change with the absorbed dose, but can be well controlled by varying the precursors concentration, beam energy, and dose rate. Increased precursor concentrations or dose rates favor nucleation, leading to the formation of smaller HR particles and increased detector sensitivity. Upon increasing the x-ray energy, growth is favored, leading to larger HR and decreased detector sensitivity. It is shown that HR and detector sensitivity are strongly correlated so that HR dictates detection sensitivity: the smaller the HR, the higher the sensitivity. Therefore, the dependence of the HR on the dose rate and on the x-ray energy establishes a new method for the controlled growth of colloidal silver, besides opening new possibilities for ionizing radiation detection.

Impact of myocardial injury after coronary artery bypass grafting on long-term prognosis.

AIMS: The most appropriate definition of perioperative myocardial infarction (pMI) after coronary artery bypass grafting (CABG) and its impact on clinically relevant long-term events is controversial. We aimed to (i) analyse the incidence of pMI depending on various current definitions in a 'real-life' setting of CABG surgery and (ii) determine the long-term prognosis of patients with pMI depending on current definitions. METHODS AND RESULTS: A consecutive cohort of 2829 coronary artery disease patients undergoing CABG from two tertiary university centres with the presence of serial perioperative cardiac biomarker measurements (cardiac troponin and creatine kinase-myocardial band) were retrospectively analysed. The incidence and prognostic impact of pMI were assessed according to (i) the 4th Universal Definition of Myocardial Infarction (4UD), (ii) the definition of the Society for Cardiovascular Angiography and Interventions (SCAI), and (iii) the Academic Research Consortium (ARC). The primary endpoint of this study was a composite of myocardial infarction, all-cause death, and repeat revascularization; secondary endpoints were mortality at 30 days and during 5-year follow-up. There was a significant difference in the occurrence of pMI (49.5% SCAI vs. 2.9% 4UD vs. 2.6% ARC). The 4th Universal Definition of Myocardial Infarction and ARC criteria remained strong independent predictors of all-cause mortality at 30 days [4UD: odds ratio (OR) 12.18; 95% confidence interval (CI) 5.00-29.67; P < 0.001; ARC: OR 13.16; 95% CI 5.41-32.00; P < 0.001] and 5 years [4UD: hazard ratio (HR) 2.13; 95% CI 1.19-3.81; P = 0.011; ARC: HR 2.23; 95% CI 1.21-4.09; P = 0.010]. Moreover, the occurrence of new perioperative electrocardiographic changes was prognostic of both primary and secondary endpoints. CONCLUSION: Incidence and prognosis of pMI differ markedly depending on the underlying definition of myocardial infarction for patients undergoing CABG. Isolated biomarker release-based definitions (such as troponin) were not associated with pMI relevant to prognosis. Additional signs of ischaemia detected by new electrocardiographic abnormalities, regional wall motion abnormalities, or coronary angiography should result in rapid action in everyday clinical practice.

Recent Advances in the Synthesis and Antioxidant Activity of Low Molecular Mass Organoselenium Molecules.

Selenium is an essential trace element in living organisms, and is present in selenoenzymes with antioxidant activity, like glutathione peroxidase (GPx) and thioredoxin reductase (TrxR). The search for small selenium-containing molecules that mimic selenoenzymes is a strong field of research in organic and medicinal chemistry. In this review, we review the synthesis and bioassays of new and known organoselenium compounds with antioxidant activity, covering the last five years. A detailed description of the synthetic procedures and the performed in vitro and in vivo bioassays is presented, highlighting the most active compounds in each series.

Synthesis of 4-(Phenylchalcogenyl)tetrazolo[1,5-a]quinolines by Bicyclization of 2-Azidobenzaldehydes with Phenylchalcogenylacetonitrile.

A general methodology to access valuable 4-(phenylchalcogenyl)tetrazolo[1,5-a]quinolines was developed by the reaction of 2-azidobenzaldehyde with phenylchalcogenylacetonitriles (sulfur and selenium) in the presence of potassium carbonate (20 mol%) as a catalyst. The reactions were conducted using a mixture of dimethylsulfoxide and water (7:3) as solvent at 80 °C for 4 h. This new methodology presents a good functional group tolerance to electron-deficient and electron-rich substituents, affording a total of twelve different 4-(phenylchalcogenyl)tetrazolo[1,5-a]quinolines selectively in moderate to excellent yields. The structure of the synthesized 4-(phenylselanyl)tetrazolo[1,5-a]quinoline was confirmed by X-ray analysis.

[Weight gain and treatment with psychotropic drugs : Background and management]. / Gewichtszunahme unter Therapie mit Psychopharmaka : Hintergründe und Management.

Psychotropic drug-induced weight gain (PIWG) is a well-known and frequent side effect which is relevant for the prognosis of patients. Individual medications have varying risks for the occurrence of PIWG, and at the same time there are individual risk factors on the part of patients, such as age, gender, metabolic and genetic factors. As the metabolic changes in the context of PIWG result in increased mortality in the long term, it is important to prevent PIWG by appropriate prevention and to intervene in a targeted manner if PIWG has already occurred. Appropriate monitoring is therefore essential. This article provides an overview of underlying mechanisms, risk constellations and possible countermeasures.

Synthesis of Seleno-Dibenzocycloheptenones/Spiro[5.5]Trienones by Radical Cyclization of Biaryl Ynones.

We report herein an alternative method for the synthesis of seleno-dibenzocycloheptenones and seleno-spiro[5.5]trienones through the radical cyclization of biaryl ynones in the presence of diorganyl diselenides, using Oxone as a green oxidizing agent. The reactions were conducted using acetonitrile as the solvent in a sealed tube at 100 °C. The protocol is operationally simple and scalable, exhibits high regioselectivity, and allows the synthesis of 24 dibenzocycloheptenones/spiro[5.5]trienones in yields of up to 99%, 17 of which are unpublished compounds. Additionally, synthetic transformations of the prepared compounds, such as oxidation and reduction reactions, are demonstrated.

Radical cyclization of alkynyl aryl ketones for the synthesis of 3-seleno-substituted thiochromones and chromones.

We report a strategy for the direct synthesis of 3-organylselanylthiochromones and 3-organylselanylchromones via the radical cyclization reaction between alkynyl aryl ketones containing an ortho-thiopropyl/methoxy group and diorganyl diselenides promoted by Oxone®. This method allows the construction and seleno-functionalization of thiochromones and chromones using Oxone® as a stable and non-hazardous oxidizing agent in the presence of CH3CN at 82 °C. These reactions tolerate a variety of substituents, and allowed the synthesis of twenty-one new 3-organylselanylthiochromones and selanylchromones in good to excellent yields (55-95%). Additionally, the developed method proved to be suitable for scale up (3.0 mmol, 80%), and the synthetic usefulness of the prepared compounds was demonstrated in the oxidation of 2-phenyl-3-(phenylselanyl)-4H-thiochromen-4-one.

Changes in athlete training patterns due to COVID-19 pandemic among Brazilian athletes.

In sports, training needs to be done according to various training patterns to optimize performance. However, this has been a major challenge to athletes due to the COVID-19 pandemic, therefore describing the impacts of lockdown caused by the COVID-19 pandemic on the athlete's training routine is necessary. 52 Brazilian athletes (Age: 31.5±10.3 years; Body Mass Index: 23.9±3.5 kg/m²), Olympic and Paralympic sports practitioners (professional and recreational) answered an online questionnaire [frequency, duration and intensity (subjective perception of effort) of training sessions], before and during lockdown (July to November/2020). The weekly training frequency (sessions/week) reduced by 48.1% (n=25) and was significantly higher among those who performed more than eight sessions before the pandemic (75% of them, p<0.000). The duration of the sessions (hours/day) decreased by 55.8% (n=29) and was significantly higher in athletes who performed training lasting more than one hour/day [75.9% of them (n=22)] and 24.1% (n= 7) performed training for more than two hours/day (p=0.132). The subjective perception of effort significantly decreased by 56%, from 8.4±1.2 to 5.5±1.7 (p=0.001). Because of the lockdown, athletes have suffered a reduction in the frequency, volume and intensity of their training sessions, but only in those with higher pre-pandemic training loads.

Transition-Metal-Free C-S, C-Se, and C-Te Bond Formation from Organoboron Compounds.

The present review describes the successful application of organoboron compounds in transition-metal-free C-S, C-Se, and C-Te bond formations. We presented studies regarding these C-Chalcogen bond formations using organoboron reagents, such as boronic acids, boronic esters, borate anions, and several sources of chalcogen atoms/moieties. Moreover, a broad range of transition-metal-free approaches to synthesize sulfides, selenides, and tellurides were described using conventional heating methods, which are sometimes green since they use green solvents, safe reagents, among others. Furthermore, protocols using alternative energy sources, including ultrasound, microwave irradiation, photocatalysis, and electrolytic processes, were also shown to be suitable. These protocols were applied to prepare a broad scope of functionalized chalcogenides with high molecular diversity. These studies and their proposed mechanisms were also reported herein in addition to the reuse of reaction promoters.

Oxone-Promoted Synthesis of 4-(Chalcogenyl)isoquinoline-N-oxides from Alkynylbenzaldoximes and Diorganyl Dichalcogenides.

We report a protocol for the synthesis of 3-organyl-4-(organylchalcogenyl)isoquinoline-2-oxides via electrophilic cyclization between alkynylbenzaldoximes and diorganyl dichalcogenides promoted by Oxone. A total of 21 3-organyl-4-(organylchalcogenyl)isoquinoline-2-oxides were selectively obtained in yields of up 93% under an ultrasound irradiation condition in short reaction times (10-70 min). Additionally, the synthetic usefulness of the 3-phenyl-4-(phenylselanyl)isoquinoline-2-oxide was demonstrated in the annulation reaction with 1-(2-bromophenyl)-3-phenylprop-2-yn-1-one and in the deoxygenation reaction with phenylboronic acid.

Synthesis of 4-Selanyl- and 4-Tellanyl-1H-isochromen-1-ones Promoted by Diorganyl Dichalcogenides and Oxone.

A new method was developed for the synthesis of 4-chalcogenyl-1H-isochromen-1-ones through the 6-endo-dig electrophilic cyclization of 2-alkynylaryl esters and diorganyl dichalcogenides under ultrasound irradiation. The reactions were performed under mild conditions, using Oxone as a green oxidant to promote the cleavage of the chalcogen-chalcogen bond in diorganyl diselenides and ditellurides to generate electrophilic species in situ. A total of 25 compounds were selectively obtained after 30-70 min, in good to excellent yields (74-95%). This procedure was extended to prepare 5H-selenopheno[3,2-c]isochromen-5-ones. Additionally, for the first time, the 4-chalcogenyl-1H-isochromen-1-ones were used as substrates in the thionation reaction, using Lawesson's reagent and microwave irradiation under solvent-free conditions, obtaining the thio derivatives in yields of up to 99% in only 15 min.

Synthesis of benzo[b]chalcogenophenes fused to selenophenes via intramolecular electrophilic cyclization of 1,3-diynes.

We describe herein an alternative and transition-metal-free procedure for the access of benzo[b]chalcogenophenes fused to selenophenes via intramolecular cyclization of 1,3-diynes. This efficient protocol involves a double cyclization of 1,3-diynyl chalcogen derivatives promoted by the electrophilic species of organoselenium generated in situ by the oxidative cleavage of the Se-Se bond of dibutyl diselenide using Oxone® in acetonitrile as solvent in an open-flask at 80 °C. In this study, 15 selenophenes with broad substrate scope were prepared in moderate to excellent yields (55-98%) with short reaction times (0.5-3.0 h).

α-Keto Acids: Acylating Agents in Organic Synthesis.

A significant number of important acyl-transfer reactions, such as direct acylation, ortho acylation, heteroatom acylation, and a diversity of cyclization reactions using the title compound as a key starting material, have been described in recent years. Just like a sleeping beauty, α-oxocarboxylic acids were awakened from a 17-year sleep to become important reagents in classical and new acylation reactions. The greener characteristic of the coproduct formed in reactions using α-keto acid (only CO2), together with its versatility as a building block in catalytic organic synthesis, accredit it as a candidate to green acylating agent, an alternative to acyl chloride, and other acyl-transfer reagents. This review presents the impressive breakthroughs achieved mainly in the past decade in the development of new catalytic reactions for the formation of C-C, C-N, and C-S bonds using α-keto acids.

Seleno-Functionalization of Quercetin Improves the Non-Covalent Inhibition of Mpro and Its Antiviral Activity in Cells against SARS-CoV-2.

The development of new antiviral drugs against SARS-CoV-2 is a valuable long-term strategy to protect the global population from the COVID-19 pandemic complementary to the vaccination. Considering this, the viral main protease (Mpro) is among the most promising molecular targets in light of its importance during the viral replication cycle. The natural flavonoid quercetin 1 has been recently reported to be a potent Mpro inhibitor in vitro, and we explored the effect produced by the introduction of organoselenium functionalities in this scaffold. In particular, we report here a new synthetic method to prepare previously inaccessible C-8 seleno-quercetin derivatives. By screening a small library of flavonols and flavone derivatives, we observed that some compounds inhibit the protease activity in vitro. For the first time, we demonstrate that quercetin (1) and 8-(p-tolylselenyl)quercetin (2d) block SARS-CoV-2 replication in infected cells at non-toxic concentrations, with an IC50 of 192 µM and 8 µM, respectively. Based on docking experiments driven by experimental evidence, we propose a non-covalent mechanism for Mpro inhibition in which a hydrogen bond between the selenium atom and Gln189 residue in the catalytic pocket could explain the higher Mpro activity of 2d and, as a result, its better antiviral profile.

Synthesis of 3,4-Bis(Butylselanyl)Selenophenes and 4-Alkoxyselenophenes Promoted by Oxone®.

We describe herein an alternative transition-metal-free procedure to access 3,4-bis(butylselanyl)selenophenes and the so far unprecedented 3-(butylselanyl)-4-alkoxyselenophenes. The protocol involves the 5-endo-dig electrophilic cyclization of 1,3-diynes promoted by electrophilic organoselenium species, generated in situ through the oxidative cleavage of the Se-Se bond of dibutyl diselenide using Oxone® as a green oxidant. The selective formation of the title products was achieved by controlling the solvent identity and the amount of dibutyl diselenide. By using 4.0 equiv of dibutyl diselenide and acetonitrile as solvent at 80 °C, four examples of 3,4-bis(butylselanyl)selenophenes were obtained in moderate to good yields (40-78%). When 3.0 equiv of dibutyl diselenide were used, in the presence of aliphatic alcohols as solvent/nucleophiles under reflux, 10 3-(butylselanyl)-4-alkoxyselenophenes were selectively obtained in low to good yields (15-80%).

Recent Advances in the Oxone-Mediated Synthesis of Heterocyclic Compounds.

Oxone is a commercially available oxidant, composed of a mixture of three inorganic species, being the potassium peroxymonosulfate (KHSO5) the reactive one. Over the past few decades, this cheap and environmentally friendly oxidant has become a powerful tool in organic synthesis, being extensively employed to mediate the construction of a plethora of important compounds. This review summarizes the recent advances in the Oxone-mediated synthesis of N-, O- and chalcogen-containing heterocyclic compounds, through a wide diversity of reactions, starting from several kinds of substrate, highlighting the main synthetic differences, advantages, the scope and limitations.

Arylseleninic acid as a green, bench-stable selenylating agent: synthesis of selanylanilines and 3-selanylindoles.

Arylseleninic acids were used as an electrophilic selenium source in aromatic substitution reactions, using N,N-substituted anilines and indoles as nucleophiles at 70 °C for 6-15 h. A total of fourteen 4-selanylanilines and five 3-selanylindoles were selectively obtained in good to excellent yields. The starting benzeneseleninic acids are easily prepared from the respective diselenides, are bench stable and easy to handle, affording water as the only waste at the end of the reaction.